In recent years great strides have been made in reducing the possibility of a fire aboard an aircraft. These improvements have dealt primarily with the use of new fire-resistant materials in the interior portions of the cabin. While these materials slow the spread of a fire, there is still the problem of toxic smoke produced by these smoldering materials. If the fire breaks out while the aircraft is at altitude, which can range up to 40,000-45,000 feet, a considerable amount of time will elapse before the aircraft can land and the passengers exit the aircraft. During this time there is a need to provide protection for the passengers. In the past the only protection offered was the use of a wet cloth placed over the face of the individual passengers and the instruction to lie as low to the floor as possible. However, it is vital during a panic situation to keep passengers in their seats as long as possible to avoid blocking access to the fire source and to maintain orderly evacuation. Also, in a crash landing where the aircraft is engulfed by fire there is no protection for the passenger from the time he leaves his seat to the point he is clear of the burning aircraft. Hence, he has no protection from falling droplets of burning materials, toxic gases, smoke inhalation or singed lungs. These are clearly not ideal solutions to the problem.
Basically, any smoke mask for a passenger on board an aircraft must have the following attributes.
1. It must be storable in a compact package and quickly accessible. PA1 2. It must be capable of coupling to a source of fresh air from the aircraft's environmental control system. PA1 3. It must also have a self-contained air or oxygen supply which can be activated in an emergency once the aircraft is on the ground so that the passenger will have breatheable air during the exiting process. PA1 4. There must also be a means to disengage from the aircraft's environmental control system fresh air supply. PA1 5. Optionally, there must also be a way to couple the smoke mask to the existing or slightly modified aircraft oxygen mask should decompression, fire and/or simultaneously smoke occur. This connection is necessary to insure that air/oxygen is available during aircraft descent from altitude.
It must be noted that it is standard airline procedure not to drop oxygen masks or to release oxygen when there is fire onboard for fear of adding fuel to the fire. But should there be a decompression due to fuselage burn through or other reason, such as, a window blow-out, it may become a requirement to deploy the existing oxygen mask, regardless of smoke environment.
There are numerous prior art smoke masks. Examples of smoke masks that provide self-contained air or oxygen breathing apparatus are: U.S. Pat. No. 456,687, "Fireman's Smoke Protector," by W. Bader; U.S. Pat. No. 1,945,919, "Life Saving Mask," by M. F. Seijo; U.S. Pat. No. 2,850,011, "Respiratory Helmet," by P. Schaefer; U.S. Pat. No. 3,521,629, "Heat and Smoke Protective Hoods," by H. I. Reynolds; U.S. Pat. No. 3,762,407, "Survival Support Device," by David E. Shonear; U.S. Pat. No. 3,976,063, "Escape Breathing Apparatus," by John W. Henneman, et al. None of these, however, disclose a method of coupling to a source of external air.
U.S. Pat. No. 521,939, "Fire Mask," by G. Pozdena, et al, discloses a mask which can be hooked up to a source of external air, so this feature by itself is old in the art. But none appear to combine the two features which are a necessity onboard an aircraft.
Oxygen masks for aircraft passengers, typically, comprise a hollow flexible cup-shaped member having a flat front face. On the face are mounted an oxygen inlet valve coupled by a line to a source of oxygen gas, a vent valve to exhaust exhaled air and a cabin air inlet valve (all simple check valves). Additionally, an elastic strap is provided for securing the mask to the passenger's head. The mask is generally stored above the passenger in a sealed compartment. Should decompression occur, the door is opened automatically and the mask drops in front of the passenger. The passenger(s) need only pull the mask toward themselves to initiate oxygen flow. Typically, solid state gas generators are used. The oxygen gas flow to the mask is only about 3 to 5% of the total air flow required and the majority of the air is drawn through the cabin air inlet valve. Thus, it can be seen that in a fire situation, the oxygen mask alone would be of little value in protecting the passenger against smoke.
Examples of aircraft oxygen masks are provided in U.S. Pat. No. 2,931,355, "System for Automatically Presenting a Breathing Mask to a Person in an Emergency," by A. E. Miller, et al; U.S. Pat. No. 3,073,301, "Aviation Quick Release Valve," by W. W. Hay, et al; U.S. Pat. No. 3,981,302, "Emergency Breathing Means," by Herbert F. Veit; U.S. Pat. No. 4,154,237, "Passenger Emergency Oxygen Mask Drop Zone Extender," by Jack P. Courter.
Thus, it is a primary object of the subject invention to provide a smoke mask which can be coupled to a compatible oxygen mask should a decompression occur concurrent with a fire onboard the aircraft or in which toxic gases or dense smoke are present.
It is a further object of the subject invention to provide a compatible smoke mask and oxygen mask wherein the oxygen mask can be releasably mounted to the smoke mask should a simultaneous fire and decompression occur.
It is another object of the subject invention to provide a compatible smoke mask and oxygen mask wherein the smoke mask can be coupled to a source of fresh air from the environmental control system of an aircraft and also incorporates a self-contained air supply and further having means to first actuate the supply of self-contained air and thereafter disconnect from the source of fresh air.